Web rewinder



March 14, 1967 s. E. AMOS 3,309,037

WEB REWINDER Filed Oct. 8, 1964 2 Sheets-Sheet 1 INVENTOR STEPHEN EARLAMOS ATTORNEY March 14-, 1967 s. E. AMOS 3,309,037

WEB REWINDER Filed Oct. 8, 1964 2! Sheets-Sheet 2 INVENTOR STEPHEN EARL'AMOS BY /%%/M' ATTORNEY United States Patent C) 3,309,037 WEB REWINDERStephen Earl Amos, Circleville, Ohio, assignor to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware FiledOct. 8, 1964, Ser. No. 402,537 3 Claims. (Cl. 242--67.3)

This invention relates to web rewinding apparatus and more particularlyto Web rewinding apparatus which maintains web alignment.

Commonly used web rewinders employ a rewind mandrel driven at a constantnumber of revolutions per minute and have flanges which are intended toprovide smooth ends on the rewound roll. One deficiency in suchapparatus is the control of web tension which is accomplished bymanually adjusting the braking on the shaft of the unwind mandrel. It isobvious as the windup roll diameter increases, and the linear speed ofthe web increases, satisfactory control of tension becomes increasinglydifficult. Another deficiency is that flanges cannot consistently effectthe necessary transverse shifting of the web, especially with thethinner gauge polymer films. The pressure (i.e., force per unit of area)are quite high along the thin edge of the film, especially if the web isunder tension suflicient to provide good tightness in the roll. Thispressure on the edge of certain tapes can be quite harmful, ofteninitiating delamination of coatings, such as magnetic coatings. In orderto avoid these deficiencies, winding speeds are often so slow as to beuneconomical.

It is, therefore, an object of the present invention to providerewinding apparatus which maintains web alignment and is capable ofrewinding a web with substantially uniform tension.

It is another object of the present invention to provide rewindingapparatus capable of elimination of irregularities from the end faces ofa roll in rewinding the roll.

It is still another object of the present invention to provide apparatusfor the rewinding of webs capable of increased speed rewinding. Theseand other objects will appear hereinafter.

These and other important objects and advantages of the invention willbecome apparent as the same is more fully understood from the followingdescription, which, taken in connection with the accompanying drawings,discloses preferred embodiments of the invention wherein:

FIGURE 1 is a view in perspective with the base plate partly cut-awaywhich illustrates the present invention;

FIGURE 2 illustrates the operation of the web alignment element of thepresent invention; and,

FIGURE 3 schematically illustrates slitting apparatus employing therewinder of the present invention.

FIGURE 1 illustrates a rewinder constructed according to this inventionin which web from supply roll 11 is wound on windup roll 12, driven bysurface contact with transport roller 13. In its passage from supply towindup, web 10 passes around guide 14 and guide 15, which are gaspermeable sleeves with air emitting from the surface at a ratesufficient to just float the web in spaced relation to the guides. Theseguides are grounded to anearth ground 16 by low resistance couplers 17,which sufiice to reduce static charges to a negligible level.

Interposed between guide 14 and guide are web twisting guides 18. Theseguides, preferably of porous metal with air emission, are covered with apermeable nylon velvet which serve to twist the web and cause lateralalignment. The use of the nylon velvet coupled with air emission servesto forcibly remove dust without abrasion. Guides 18a and 18b are spacedapart sufliciently to permit web 10 to pass between them free of partialwrap around contact; however, to provide the greatest latitude ofutility without the necessity of adjusment, guide 18a is in a slightlystaggered relationship to guide 1812, i.e., one is positioned fartheralong in the direction of web motion than the other, which is on theopposite surface of web surface. This arrangement permits a wider gapbetween the individual elements of this guide while still permittingeach element to effectively perform its twisting function.

Continuing in reference to FIGURE 1, web 10, which in the preferredembodiment returns to its initial plane by guide 15, passes successivelyto guides 19 and 20 which feed it to transport roll 13, about which itpartially wraps before passage to windup roll 12. As the diameter ofroll 12 increases with web windup, the axis moves along linear track 21away from transport roller 13. The periphery of roll 12 is urged intocontact with roller 13 by spring means 29, which exerts pressure on theaxis.

For maintenance of control over supply roll 11 to avoid free-wheeling,or overrunning when stopping, the mandrel of this roll is provided withmeans for braking. Shown in FIGURE 1 is adjustable compressed air brake22. Brake shoe 23 presses in frictional contact with cylindrical hub 24which is co-axially mounted on the shaft of roll 11 so as to engage thecore of roll 11 and rotate therewith. Shoe 23 is urged into contact withthe hub by compressed air cylinder 25, with pressure of the shoe againstthe hub controlled by the adjusting of the air, by means of valve 26 theapplied pressure is indicated by gauge 27. This braking mechanism isshown above deck 28, which requires that hub 24 be removable and brake22 be pivoted on deck 28 to swing away to permit roll changes; however,this mechanism can be mounted below the deck if desired. Optionally, inplace of an air brake, other types such as an adjustable, spring-loadedbrake or a magnetic brake, as is known to those skilled in the art, aresatisfactory.

To illustrate elements of the present invention normally positionedbelow deck 28, cutaway section 30 is provided in the drawing ofFIGURE 1. Shown in the cutaway is torque motor 31, which is mounted,preferably with ball-bearing guides on tracks 32 and 33, so that itsaxis and also that of the windup roll 12 can move away from the axis oftransport roller 13 as the diameter of the roll increases. Torque motor31 drives roll 12, and roller 13 is driven by a separate motor (notshown). The torque of motor 31 is small in comparison to that of themotor which drives roller 13, and is used for its inertial effect toprevent free wheeling of roll 12. This motor supplies a constant torque,independent of speed, and has little tendency to overdrive the roll;thus, the winding torque is supplied in part by surface wind in contactwith axially driven roller 13. Peripheral contact between roller 13 androll 12 has an additional function, however, in supplying ironing actionto exclude air between film convolutions in roll formation. Springs 29are mounted within channel tracks 32 and 33 so as to urge roll 12 inperipheral contact with roller 13. Only light contact is required toeflect winding, since roller 13 preferably is equipped with a rubbertire for effective friction.

Shown through cutaway 34 is air line 35 which is coupled to a source ofcompressed air to provide air to the porous web guides, as shown toguide 15, which is illustrative of the manner of coupling to all of theporous guides. The flow of air through the guides is controlled byneedle valve 36, which controls the flow to all guides; optionallyindividual needle valves can be provided for each guide. Air to brake 22can be supplied from the same source as for the guides, which is shownas line 35.

An important element of the present invention is that for the rotationof the plane of the web to elfect lateral align-ment. This isillustrated as the combination of vertical guides 14 and 15 withhorizontal guides 18a and 18b.

Patented Mar. 14, 1967 Reference to FIGURE 2, a schematic projection,will facilitate understanding of rotation to effect lateral alignment ofthe web or the removal of transverse sway. Guide14 and guide 15, withparallel faces, define a vertical planar path for web 10. Interposed onthis path between guides 14 and 15 are guides 18a and 18b, with adjacentfaces defining a gap for passage of web 10 therebetween. This gap, shownas substantially at right angles to the plane of the web as defined byguides 14 and 15, is positioned so that its center line 45 and its axisof rotation A-A from the initial plane of the web is along intendedcenter line 37 of web 10. A position of web 110 such that the centerline of the web coincides with the in-, tended center line will resultin edges 38 and 39 being.

of equal length; the web in its passage through this alignment elementwill thus have no lateral motion along guides 14 and 15. On the otherhand, if due to improper roll formation with lateral weave, the webrises on guide 14, then the path traversed by edge 39 will be greaterthan the path traversed by edge 38. The longer path causes greatertension on edge 39, which causes downward motion along guide 14 torestoresymmetry of Web-10 about center line 37 and pivot axis AA andachieve equality of forces along the edges of the web. It is apparentthat web 10 must be free to move transversely. along the face of guide14 in order to respond to restoring forces and achieve alignment.Flanges on air sleeves 15, 19 and 20 are preferred to prevent transversemotion of the web after passing pivot axis A Further, it should beobserved that guide 15 which serves to restore web 10 to its initialplane, also can effect further alignment where the weave may not befully removed by passage over the span between guide 14 and guide 18.For example, while the motion of the web is a result of restoring forcesarising from the unequal length of edges 38 and 39 has been illustratedas along guide 14, in practice it can be divided. between guide 14 andguide 18. Thus, for example, it is possible that only one-half the weavewill be removed by the first span; the second span between guide 18 andguide 15 can thus remove the remaining one-half weave. Therefore, it isapparent that the use of film rotation is not restricted to a singlestation but can be repeated, as often as required to effect properalignment.

In consideration of the necessity for free lateral motion, transverse tothe direction of web motion, it is essential to have friction as low aspossible. While driven or idle rolls can be effective for heavy gaugewebs, they are not generally suitable for thinner gauges. Thus, totransport thinner gauges at minimum tension, which can not drive idlerrollers, and where speed control of driven rollers can be prohibitivelydifficult, and to provide for the maximum freedom of transverse motion,air guides are essential. These guides,-constructed of a porous,sintered metal which is grounded, provide a floating path for the weband also remove static charges and dust while efliecting control of theweb with a minimum of friction. In FIG- URE 1 all guides except 14 areshown as having flanges, while in FIGURE 2, no flanges are shown;generally flanges are optional after guideslSa and 18b, but arepreferred if winding is at high speeds. The width of the spool or guidebetween flanges should be adequate to accommodate web weave of highamplitude without contacting the flanges, which are employed to preventweb spilling under extreme cases.

FIGURE 3 schematically illustrates the rewinder of the present inventionadapted to slit and rewind a web as a plurality of webs or strips. Shownin the drawing, web 10 is slit into four narrow widths which are woundon four rolls 40, 41, 42 and 43 disposed around, and in contact withtransport roller 13, by three parallel knives, of which knife 44 isshown. These edges of these knives are in direct contact with guide 20,which has gaspermeable flanges to prevent misalignment of the web duringslitting; Takeup rolls 40, 41, 42 and 43 are provided With appropriatedriving means, such as torque motors and ways or tracks as describedhereinbefore to permit the rolls to move away from the transport drum asthe diameter increases upon winding.

What is claimed is: 1. An apparatus for handling a running webcomprising, in combination: a web supply source; a driven transportroller about which said web partially wraps; a windup roll adapted forsurface wind having an axis adapted to recede from said transport rolleras the diameter of said windup roll increases upon winding, said winduproller being in driven peripheral contact with said transport roller;first web guide means positioned between said web source and saidtransport roller and intermediate web guide means positioned betweensaid first web guide means each having a gas permeable metal surface,coupled to a ground; a source of compressed gas coupled to said webguide means to float said web in spaced relationship thereto, thesurface of at least one of said intermediate web guide means positionedat an angle to the surfaces of said first web guide means positioned oneach side of said intermediate web guide means, the central axis of saidangle being along the intended center line of said, web wherebyalignment of said running web is maintained.

2. The apparatus of claim 1 wherein said angle is substantially at rightangle.

3. An apparatus for handling, a running web comprising, in combination:a web supply roll; a windup roll adapted for surface wind;-a rubbervcovered driven transport roller about which saidweb partially wraps andin peripheral driving contact with said windup roll; means connected tothe axis of said windup roll to linearly recede saidwindup roll fromsaid transport roller as the diameter of said windup roll increases uponwinding; first and second spaced apart, gas permeable, metal surface webguides coupled to a ground, positioned between said supply roll 45 andsaid transport roller; a pair of gas permeable, metal surface web guidespositioned between said first and second web guides adapted for passageof said web therebetween free of partial wrap around contact and adaptedto rotate said web through a substantially right angle with 5 an axis ofrotation coinciding with the intended center line of said web betweensaid first and second web guides; and a source of compressed gas coupledto said web guides to float said web in spaced relationship thereto.

FRANK I. COHEN, Primazy Examiner. GEORGE F. MAUTZ, Examiner.

3. AN APPARATUS FOR HANDLING A RUNNING WEB COMPRISING, IN COMBINATION: AWEB SUPPLY ROLL; A WINDUP ROLL ADAPTED FOR SURFACE WIND; A RUBBERCOVERED DRIVEN TRANSPORT ROLLER ABOUT WHICH SAID WEB PARTIALLY WRAPS ANDIN PERIPHERAL DRIVING CONTACT WITH SAID WINDUP ROLL; MEANS CONNECTED TOTHE AXIS OF SAID WINDUP ROLL TO LINEARLY RECEDE SAID WINDUP ROLL FROMSAID TRANSPORT ROLLER AS THE DIAMETER OF SAID WINDUP ROLL INCREASE UPONWINDING; FIRST AND SECOND SPACED APART, GAS PERMEABLE, METAL SURFACE WEBGUIDES COUPLED TO A GROUND, POSITIONED BETWEEN SAID SUPPLY ROLL AND SAIDTRANSPORT ROLLER; A PAIR OF GAS PERMEABLE, METAL SURFACE WEB GUIDESPOSITIONED BETWEEN SAID FIRST AND SECOND WEB GUIDES ADAPTED FOR PASSAGEOF SAID WEB THEREBETWEEN FREE OF PARTIAL WRAP AROUND CONTACT AND ADAPTEDTO ROTATE SAID WEB THROUGH A SUBSTANTIALLY RIGHT ANGLE TO AN AXIS OFROTATION COINCIDING WITH THE INTENDED CENTER LINE OF SAID WEB BETWEENSAID FIRST AND SECOND WEB GUIDES; AND A SOURCE OF COMPRESSED GAS COUPLEDT SAID WEB GUIDES TO FLOAT SAID WEB IN SPACED RELATIONSHIP THERETO.